The present invention is concerned with a valve construction, and more particularly with a valve adapted for use in the intravenous supply of liquid products.
The valve of the present invention was designed for, and has particular utility with regard to, the intravenous supply of fluids to a patient. More specifically, it is a relatively common medical practice, to establish an intravenous connection with a patient, and through the use of a multi-port valve connected to said supply tube, administer fluid products such as blood, blood plasma, medications, etc. to the patient. Application of the fluid product is normally done through the use of gravity with the supply vessels for the fluid products suspended above the patient, and a clamp or pinched valve used to regulate the rate of flow to the patient. In addition to the clamp or pinch valve, a multi-port valve is normally connected to said supply tube above the pinch valve, which enables the selective supply of one or more fluid products. Examples of valves of this type, which are termed "I.V. valves," can be found in U.S. Pat. Nos. 3,481,367 and 3,750,704.
Since the medications supplied to one patient, might not be compatable with another, the I.V. valves must be cleaned and sterilized before it can be reused. This however is not practical, thus, in many instances, the I.V. valves are merely discarded. As can be appreciated, the cost of these I.V. valves can become a significant factor, and efforts have been made, as noted in the above-mentioned patents, to provide relatively inexpensive, disposable I.V. valves.
While the prior art attempts mentioned above have been partially successful, the present invention provides an improved, extremely simple and ingenous approach to the design and production of a disposable, intravenous valve. As will become clear from the discussion to follow, the present invention enables an I.V. valve to be fabricated inexpensively, and from but two molded parts which have been designed not only to minimize the cost of production tooling, but also to maximize the number of parts which can be molded during each cycle of the injection molding apparatus. These features will of course reduce the production cost for each valve. In addition, the structural features of the present invention provide a novel approach to the problem of multi-port selective valving.
More specifically, the present invention provides a valve body which includes a substantially cylindrical valve chamber into which the inlet and outlet ports open. A plug member of unique design is disposed in said valve chamber for rotation with respect thereto. The plug member includes an end segment that may be spaced from the bottom of the valve cavity to define therewith a valve chamber, and, in the preferred, illustrated embodiment is hollow. One or more axially elongate, concave portions are formed in the end segment, with the remainder of the surface portion of the end segment being of an arcuate convex configuration. The end segment is fabricated from a relatively flexible material and is of a diameter slightly larger than the diameter of the valve cavity. Accordingly, upon assembly the end segment will be resiliently deformed, with the resulting resiliency forcing the convexed surface portions of the end segments into tight sealing engagement with the cavity surface wall. Correspondingly, the concave portions of the end segment will cooperate with the valve cavity surface wall to define axially extending channels opening to the valve chamber. Accordingly, by the selective rotative positioning of the plug member, one or the other or both of the inlet ports may be interconnected with the valve chamber, or alternately blocked as may be desired.
As an additional feature, the present invention also contemplates the employment of a valve body wherein the outlet port axis is aligned with either the valve cavity axis or the axes of the inlet port. Accordingly, during molding of said valve body, only a single side action for retraction of the mold cores will be required. That is to say, that the parting of the mold halves will pull the necessary cores in a first general direction, for example along the X axis, with the single side action pulling the necessary cores along the Y axis. This is a significant improvement over the prior art designs of the above-mentioned type, wherein the inlet and outlet ports are disposed along one pair of axes, i.e X and Y, with the valve cavity disposed along a third axis. Accordingly, in the molding operation at least two side actions are required to pull the cores used to form the bores. This materially reduces the number of valve bodies that can be molded with each cycle of the injection molding machine, and most importantly, complicates the design of and increases the cost of the production tooling.
In addition to the above specifically discussed features and advantages of the invention, other such features and advantages will become apparent from the detailed description of the preferred embodiment which follow hereinafter in conjunction with the drawings.